An outbreak of Hemophilus influenzae type b meningitis in an enclosed hospital population.

Five cases of HITB maningitis occurred within six months in an enclosed population of 28 to 32 chronically ill children. Studies of nasopharyngeal carriage and serum HITB anticapsular antibodies were started after the third case occurred. Two patients had low (less than 0.04 and 0.05mug/ml) antibodies and were not carriers when studied prior to onset of their disease. The carriage rate was approximately 20% among the children. Carriage was usually prolonged, and acquisition was not prevented by high antibody levels. Attempts to arrest this outbreak with type b polysaccharide immunization and ampicillin therapy are discussed in the context of HITB meningitis as a contagious disease.